柔性冗余度机器人振动主动控制

采用振动主动控制方法降低柔性冗余度机器人的弹性动力响应。设计了具有压电作动器与应变传感器的机敏连杆 ,建立了离散时变受控系统的状态空间表达式。利用 Bellman动态规划设计 L QR状态反馈控制器 ,并提出了一种状态估计的近似方法。平面 3R柔性冗余度机器人的仿真算例表明 ,采用该方法可以使柔性冗余度机器人的动力学性能得到显著的改善     

机械系统可靠性的动态优化设计

通过运用动态规划法原理和网络图方法,探讨了在机械系统设计中,既要使系统的可靠性最高,又要使系统的生产成本最低的机械系统的动态优化设计的原理和方法,通过实例分析证明此方法可以有效地解决机械系统可靠性问题.     

一类混合时滞系统的观测器设计

对于一类具有状态和有限自动机输出时滞的离散混合系统,给出了混合观测器的设计方法。观测器由一个位置观测器和一个离散状态观测器组成。前者应用自动机观测器来确定混合系统的当前位置,后者应用龙伯格观测器对系统离散状态的演化进行估计。对于每一个独立的观测器,系统的信息往往不完全,为了在这种情况下仍能应用混合观测器对系统进行观测,在两类独立观测器的基础上给出了一个新的信号产生器,将两类观测器有机结合起来。同时给出了信号产生器中决策函数的充分条件,进一步得到了整个混合观测器指数收敛的充分条件。保证该混合观测器能在有限步内判断出系统的当前位置,同时指数收敛于真实离散时间状态。最后,给出了仿真例子说明设计方法的可行性和有效性。     

Adaptive spectral band identification method in noncontact temperature measurement based on dynamic programming

An adaptive method based on dynamic programming is proposed to identify the spectral band for noncontact measurement of surface temperature of heatshield materials when Fourier transform infrared (FTIR) spectrometer is used to collect the radiation spectrum in the dynamic heating environment of a high-frequency plasma wind tunnel. First, the radiation spectrum is converted to a time series. Then, high-frequency parts of the measurement spectral signal are obtained by multi-resolution analysis of one-dimensional discrete wavelet and then the suitable spectral band required by a noncontact temperature measurement is adaptively identified based on dynamic programming. Eventually, surface temperature and its corresponding emissivity can be determined. Results of the experiment conducted on a benchmark material (graphite) in the dynamic heating environment of high frequency plasma wind tunnel show the proposed method to be practical.     

基于改进粒子群算法的供应商参与可靠性设计优化

研究供应商参与下的汽车产品子系统可靠性设计的优化问题,考虑供应商参与产品设计的可信度因素,建立以最大化系统的可靠度和供应商的可信度为优化目标的多目标数学规划模型。通过加权的方法把多目标优化模型转化为单目标非线性整数规划模型。采用粒子群(Particle swarm optimization,PSO)算法进行求解,提出适用于“零部件—供应商”关系的离散粒子编码方法。设计带有自适应动态惩罚项的适应度函数,把优化问题转化为无约束优化问题,并将粒子的搜索范围扩展到近可行解空间,进而较好地改进了算法的搜索速度和收敛性能。以某中级轿车传动系统零部件可靠性设计的优化问题为实例,进行仿真研究,应用质量功能展开和模糊评判的方法生成了零部件的权重和供应商可信度初始数据值,仿真结果验证了所提出PSO算法的实用性和有效性。     

Robust preview control for a class of uncertain discrete-time systems with time-varying delay

This paper proposes a concept of robust preview tracking control for uncertain discrete-time systems with time-varying delay. Firstly, a model transformation is employed for an uncertain discrete system with time-varying delay. Then, the auxiliary variables related to the system state and input are introduced to derive an augmented error system that includes future information on the reference signal. This leads to the tracking problem being transformed into a regulator problem. Finally, for the augmented error system, a sufficient condition of asymptotic stability is derived and the preview controller design method is proposed based on the scaled small gain theorem and linear matrix inequality (LMI) technique. The method proposed in this paper not only solves the difficulty problem of applying the difference operator to the time-varying matrices but also simplifies the structure of the augmented error system. The numerical simulation example also illustrates the effectiveness of the results presented in the paper.     

混合动力汽车能量管理策略的四步骤设计方法

以行星齿轮结构的混合动力汽车的动力系统为研究对象,提出了一套能量管理策略的四步骤设计方法。第一步,引入混杂动态系统理论来描述既有离散事件动态系统特征又有连续变量动态系统特征的混合动力系统;第二步,利用序列二次项规划算法和动态规划算法分别求解出最佳功率分配和最佳工作模式切换序列的基本规律;第三步,建立基于规则和模糊规则的能量管理策略;第四步,利用遗传算法对第三步已经建立的工作模式切换规则和功率分配的模糊控制规则中的参数进行优化,以获得更佳的控制效果。     

基于数字孪生的复杂产品离散装配车间动态调度

面向多品种变批量生产的复杂产品离散装配车间是典型的复杂制造系统,其运行过程呈现高复杂性、强动态性和不确定性因素多等特征,为实现复杂产品离散装配车间的动态调度,提出一种基于数字孪生的复杂产品离散装配车间动态调度方法,通过物理空间和虚拟空间之间的数据交互进行更精确的动态调度。构建了基于数字孪生的复杂产品离散装配车间调度框架和调度问题模型,详细阐述了基于实时数据和神经网络的工时在线预测、面向复杂产品离散装配的数字孪生车间动态调度等关键实现技术;构建了复杂产品离散装配车间调度系统,并以某航天产品装配车间的调度过程为例,验证了该方法的有效性和可行性。     

基于趋近律离散滑模控制的柔性梁振动抑制

研究了基于趋近律的离散滑模控制在智能柔性悬臂梁振动控制中的应用.以压电陶瓷为作动器,电阻应变片为传感器,采用有限元方法和模态截断技术建立结构动力学模型.由于柔性结构系统受到不确定外部扰动和量测噪声的影响以及参数的不确定性,滑模变结构控制可以实现滑动模态与系统的外干扰和参数摄动无关,即滑动模态的不变性.结构振动控制在系统状态由于外部干扰的影响偏离平衡状态,在控制器作用下能使系统趋于零状态.采用趋近律离散滑模控制方法设计状态调节器.由于状态量不能直接测量,故利用离散卡尔曼滤波技术构造状态估计器.采用试验模态测试方法得到结构的前4阶固有频率和阻尼比,与有限元方法的结果比较,说明该模型的正确性.使用dSPACE实时仿真系统和MATLAB/Simulink搭建控制系统,进行了振动主动控制试验.试验结果表明,所设计的控制器能有效抑制结构的振动响应.     

A 4-layer method of developing integrated sensor systems with LabVIEW

System integrity is important for fast and accurate measurement and control.LabVIEW is widely used in education and industry.Many LabVIEW codes are hard to be read and shown because of their 2D topology.In order to simplify the programming,a 4-layer model of developing sensor or measurement systems with LabVIEW is proposed in this paper.The purpose of this paper is to show the readers how to design simple,clear and strong automated systems with LabVIEW.Using a Sensirion SHT75 humidity sensor and an NI USB6008 DAQ board as an example,this paper describes the steps of developing a sensor system from the physical layer to application layer in detail.In layer 2,port selection and signal regulation are demonstrated.In layer 3,timing waveform analysis and synthesis,state diagram analysis,instruction set design,micro operation and fault tolerance designs are demonstrated.In layer 4,data visualization is covered with a vivid example.Programmers found it was hard to show readers their LabVIEW codes because many LabVIEW codes occupy several screens.A layer model simplifies the programming,so one is able to show a medium size LabVIEW code easily.     

云制造环境下基于离散Markov跳变系统的机床装备资源动态优选方法

针对云制造环境下加工任务执行过程中机床装备资源易受紧急插单、加工质量异常、设备运行故障等高频随机扰动影响,致使产品加工服务质量(QoS)不能满足客户个性化需求的问题,提出一种基于离散Markov跳变系统的机床装备资源动态优化选择方法.首先,结合云制造服务运行特点,构建了云制造环境下面向加工任务执行过程的服务质量动态演化...     

离散型整星隔振系统的动力学参数设计

研究离散型整星隔振系统的动力学参数设计问题。通过建立整星隔振系统的动力学模型,得到从隔振器底端到卫星质心的振动传递率。用理论和仿真方法对此动力学模型进行有效验证,表明该动力学模型能较好地体现离散型整星隔振系统前两阶的振动传递规律。通过衰减不同的共振峰值的内在规律,讨论该隔振系统动力学参数对振动传递特性的影响,提出离散型整星隔振系统的动力学参数设计原则,为整星隔振器的结构参数设计提供理论指导。利用振动台对离散型整星隔振系统进行振动试验,表明该隔振器具有很好的隔振性能,验证了动力学参数设计的正确性。     

Comprehensive analysis of the influence of structural and dynamic parameters on the accuracy of nano-precision positioning stages

Nano-precision positioning stages are characterized by rigid-flexible coupling systems. The complex dynamic characteristics of mechanical structure of a stage, which are determined by structural and dynamic parameters, exert a serious influence on the accuracy of its motion and measurement. Systematic evaluation of such influence is essential for the design and improvement of stages. A systematic approach to modeling the dynamic accuracy of a nano-precision positioning stage is developed in this work by integrating a multi-rigid-body dynamic model of the mechanical system and measurement system models. The influence of structural and dynamic parameters, including aerostatic bearing configurations, motion plane errors, foundation vibrations, and positions of the acting points of driving forces, on dynamic accuracy is investigated by adopting the H-type configured stage as an example. The approach is programmed and integrated into a software framework that supports the dynamic design of nano-precision positioning stages. The software framework is then applied to the design of a nano-precision positioning stage used in a packaging lithography machine.     

混合变量非线性规划问题的差异演化算法研究

针对机械优化设计问题中的混合变量非线性规划问题,提出一种改进的差异演化算法.首先针对混合变量非线性规划问题的特点,采用离散变量与连续变量分别进化策略,以使差异演化算法能够适于解决这类问题.其次,依据基因突变原理,提出突变因子的概念,使群体中的一部分个体不经过交叉操作,而直接与父代竞争,提高了群体的多样性,增强了算法的全局搜索能力,并对差异演化算法的缩放因子进行线性递减计算,加快了算法的收敛速度.测试结果表明,所提出算法不仅能够解决混合变量非线性规划问题,而且有较快的收敛速度和较好的全局收敛能力,实用价值明显.     

基于PLC的LT风洞内三维高精度探针定位系统

机翼模型受力试验是飞机翼型设计必不可少的关键环节,风洞是进行空气动力学试验的必备装置。该文介绍了基于LT(低湍流)风洞的探针三维高精度位移测控系统的组成,详细分析了LT风洞现场实验条件及应满足的控制要求,在此基础上,论述了系统的总体设计方案,硬件结构和触摸屏的组态过程,重点论述了PLC的硬件配置及控制软件的设计。运行实践证明,该系统满足设计要求,运行可靠。有效地解决了翼型实验研究中探针在风洞中准确定位控制的难题。     

Optimal replenishment policies for deteriorating control wafers inventory

This paper considers a control wafers replenishment problem with inventory deterioration. In the process, control wafers begin to deteriorate after the pre-disposition. The objective of this research is to minimize the total cost of control wafers, where the cost includes ordering cost, holding cost and purchase cost. We first formulate the control wafers inventory problem as a dynamic programming model. We then transform the control wafers’ inventory problem into the mixed 0–1 linear programming model. An illustrative example with four cases is used to illustrate the practicality of these models, and sensitivity analysis is applied to understand the impact of parameters to these models. The results demonstrate that the proposed mixed 0–1 linear programming model is an effective tool for determining the replenishment of control wafers for multi-periods.     

确定离散动力系统分叉点的最优化方法

根据离散动力系统在分叉点处的动力学特性 ,研究了进化规划求解倍周期分叉点的模型 ,包括适合度函数 ,变异算子。提出了基于进化规划的计算混沌动力系统分叉点的新方法 ,通过对 L ogistic映射动力系统的倍周期分叉问题的数值仿真 ,获得了较为精确的结果 ,表明这将是通向混沌的快速之路     

Robust extended Kalman filter of discrete-time Markovian jump nonlinear system under uncertain noise

This paper examines the problem of robust extended Kalman filter design for discrete-time Markovian jump nonlinear systems with noise uncertainty. Because of the existence of stochastic Markovian switching, the state and measurement equations of underlying system are subject to uncertain noise whose covariance matrices are time-varying or un-measurable instead of stationary. First, based on the expression of filtering performance deviation, admissible uncertainty of noise covariance matrix is given. Secondly, two forms of noise uncertainty are taken into account: Non-Structural and Structural. It is proved by applying game theory that this filter design is a robust mini-max filter. A numerical example shows the validity of the method.     

倾转旋翼机过渡段动态最优控制技术研究

针对倾转旋翼机的最优过渡问题，采用动态最优控制来减小过渡时间、姿态角变化以及缓解驾驶员工作负荷。在飞行动力学模型的基础上引入操纵方程，通过引入操纵量方程来缓解操纵量的跳变；随后将飞行器的最优动态倾转过渡过程转变成非线性动态最优控制问题，引入合理的性能指标，基于序列二次规划算法进行求解；最终以XV-15为例，分析系统各个通道抗风扰能力以及进行全航线飞行仿真。实验结果表明，所设计的过渡段最优控制在倾转旋翼机的各个通道抗风扰性能突出，系统鲁棒性较好，具有较好的实际应用价值。